It is common that positive active materials for non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries and sodium-ion secondary batteries contain rare metals such as cobalt and nickel. However, such metals are available in small quantities and are expensive. In contrast, sulfur is currently available in a large quantity. Therefore, focus has been being placed on techniques in which sulfur (S) is used as a positive active material and silicon (Si) or tin (Sn) is used as a negative active material (see JP 2005-251469 A and JP 2013-191331 A, for example). It is said that, if sulfur is used as the positive active material of a lithium-ion secondary battery, the charge/discharge capacity of a lithium-ion secondary battery using sulfur alone as the positive active material is about six times or more the charge/discharge capacity of a lithium-ion secondary battery using a common lithium cobalt oxide positive electrode material, for example.
In the related art, a positive active material or a negative active material, a binder resin, and a conductive assistance are dispersed in a solvent to prepare slurry. The slurry is applied onto a plain metal foil that serves as a current collector, and the solvent in the slurry is dried and removed to form a mixture layer. The current collector and the mixture layer thereon are compacted using a roll pressing machine, and the binder resin is cured to fabricate a positive electrode and a negative electrode. Lithium is ionized and moved between the positive electrode and the negative electrode to serve as a substance (so-called charge carrier or carrier) involved in charge and discharge. In the related art, lithium is contained in an electrolyte and the positive active material.